"After being glued to the first two seasons of The Crown, I am beyond thrilled to be joining the cast of this incredible piece of television. Snowdon was such a dynamic and complex man. I'm really looking forward to playing him," Daniels said in a statement.

Matthew Goode played the role of Princess Margaret's free-spirit husband in Season 2 of the show.

The period drama about Britain's long-reigning Queen Elizabeth II has been entirely re-cast after a time jump in the narrative, with Olivia Colman taking over as the monarch from previous portrayer Claire Foy; Tobias Menzies replacing Matt Smith as Prince Philip and Helena Bonham Carter replacing Vanessa Kirby as Margaret.